Hmmmm...data error?

[sniper]

For years, have been shooting 150-158 gr. cast boolits over 5.5 gr. Unique from my 4" 357 Magnum revolvers, 357 brass, standard primers. As near as I can figure, that should be about a +P load, going by the figures given to me when they chrono'ed my loads as 860 fps at IPSC matches. Reading, I find lower loadings...4.5-5.0 gr. loads seem to give higher velocities. "Passing strange" sez I.

Is there someone out there with Quickload or the equivalent that is willing to run the figures, and tell me if what I have been given is accurate, and if not, what level load should give me a load somewhat less than 1,000 fps? I find, as I have bought available powder, I now have Unique, AA #5, Universal, 800-X and Trail Boss. Some of which should put me in the ballpark.

Thank you! :smile:

[trails4u]

Would need COAL and actual bullet profile to give you anything useful. They can make a huge difference in pressure, thus velocity.

[sniper]

Coal 1.590" Bullet profile...RCBS 150 gr. SWC, and 158 gr. Gas checked SWC. Is that what you need?

[trails4u]

285192

I couldn't find that exact bullet profile in my library, but chose the 38-158-RN and bumped the weight to 158 for the calculation.

QL is not know for being completely reliable in straight-walled stuff, but FWIW, shows 927fps at just below 20Kpsi for what I ran..... Use as you wish, but it's not seemingly the exact boolit you're using, so buyer beware.

[ddixie884]

I think you are pretty close. Alliant says 5.2gr with 158gr speer bullet in a .38spl case gives 919 fps.............

[charlie b]

.... Reading, I find lower loadings...4.5-5.0 gr. loads seem to give higher velocities. "Passing strange" sez I.


Be careful of what you read about loads. Published data can be misleading given the different test setups. Check for barrel lengths used for the data. If a test barrel is used make sure they mention that it is 'vented' for revolver loads. If loads are read about online then things like different bullets, OAL, primers, altitude, temperature, etc can make a difference. And different mfgs have slightly different spacing between cylinder and barrel.

[sniper]

:cool: Thanks!

[44MAG#1]

For years, have been shooting 150-158 gr. cast boolits over 5.5 gr. Unique from my 4" 357 Magnum revolvers, 357 brass, standard primers. As near as I can figure, that should be about a +P load, going by the figures given to me when they chrono'ed my loads as 860 fps at IPSC matches. Reading, I find lower loadings...4.5-5.0 gr. loads seem to give higher velocities. "Passing strange" sez I.

Is there someone out there with Quickload or the equivalent that is willing to run the figures, and tell me if what I have been given is accurate, and if not, what level load should give me a load somewhat less than 1,000 fps? I find, as I have bought available powder, I now have Unique, AA #5, Universal, 800-X and Trail Boss. Some of which should put me in the ballpark.

Thank you! :smile:

Do you have the same gun the higher velocities were chronoed from?
Do you have the exact same "lot" of powder the higher velocities were obtained with?
Do you have the exact same "lot" of primers used in the higher velocity load?
Did you chrono in the same temperature the higher velocity loads were chronoed in?
Did you use the exact same bullet the higher velocity loads used?

Many things to consider. You will get many answers on this from the relatively inexperienced to those that have thousands of dollars worth of equipment and more firearms than the US Army. Ballistics are an ever changing thing. Components are an ever changing thing. Firearms are an ever changing thing. Nothing is irrefutable fact in ballistics.
Just trying to be realistic is all with what I am saying and not trying to make anyone mad.

[sniper]

Do you have the same gun the higher velocities were chronoed from?
Do you have the exact same "lot" of powder the higher velocities were obtained with?
Do you have the exact same "lot" of primers used in the higher velocity load?
Did you chrono in the same temperature the higher velocity loads were chronoed in?
Did you use the exact same bullet the higher velocity loads used? Nothing is irrefutable fact in ballistics.
Just trying to be realistic is all with what I am saying and not trying to make anyone mad.

The obvious answer is "OF COURSE NOT". Thankfully, precious few shooters indulge in that foolish sort of ballistic proctology.
Unless something is radically WRONG and is pushing the envelope on either side, a load for one handgun/rifle caliber published by a reputable source, WILL be "close" to another's in similar circumstances. NOT perfect by any means, and may need some tweaking, but for those of us not blessed with a climate controlled shooting laboratory and many electronic gizwillies, a careful "good enough" has done just fine for decades.

[44MAG#1]

The obvious answer is "OF COURSE NOT". Thankfully, precious few shooters indulge in that foolish sort of ballistic proctology.
Unless something is radically WRONG and is pushing the envelope on either side, a load for one handgun/rifle caliber published by a reputable source, WILL be "close" to another's in similar circumstances. NOT perfect by any means, and may need some tweaking, but for those of us not blessed with a climate controlled shooting laboratory and many electronic gizwillies, a careful "good enough" has done just fine for decades.

You were the one that made the original post.

[QuackAttack24]

A couple days ago I just put some 158gr LSWC-PC,GC bullets down range. Fired from model 27 6" barrel using 5.4 gr of Unique, 38 Sp cases COAL 1.375, I got 1048ft/s using Labradar. When bumping the charge up to 6 gr of Unique and firing the same bullet from 357 mag cases, COAL 1.590, the velocity dropped to 1030. Extra room in the 357 case probably means lower pressure and therefore velocity. The numbers you have been given sound about right given your shorter barrel length and lighter charge of Unique than my 357 load.

[44MAG#1]

A couple days ago I just put some 158gr LSWC-PC,GC bullets down range. Fired from model 27 6" barrel using 5.4 gr of Unique, 38 Sp cases COAL 1.375, I got 1048ft/s using Labradar. When bumping the charge up to 6 gr of Unique and firing the same bullet from 357 mag cases, COAL 1.590, the velocity dropped to 1030. Extra room in the 357 case probably means lower pressure and therefore velocity. The numbers you have been given sound about right given your shorter barrel length and lighter charge of Unique than my 357 load.

What you are stating is nothing new. I occassionally seat the "250 Keith" deep in the 44 Magnum cases. I seat it to the OAL of the 44 Special and use 44 Special data. When seated to "normal" OAL in the magnum cases I have to add at least one more grain of Unique to get the same velocity. At least one more grain using the same primers and "lot" of powder.
I deep seat quite often and like doing so.
Many with little experience to large amounts of experience with more firearms than the US Army and thousands of dollars of equipment will probably chime in on this.
Just my 1.5 cents worth on this.

[QuackAttack24]

Of all the powders you list, I have Unique, AA #5, and Trail Boss. I've only run Trail Boss and Unique past a chrono with the 158 LSWC. I can almost guarantee that you could completely fill a 357 case with Trail Boss up to the base of the bullet (not compressed), and it will chrono at less than 1000 ft/s. I've shot 38 Sp. with 4.0 gr Trail Boss and get 805 ft/s from a 6" model 19. The max listed load for 357 is 4.2 gr. I've never seen any Trail Boss load go over 1000 in any caliber, or get close for that matter. They do say completely filling the case up to the base of the bullet is safe for any caliber.